adjust cya before or after shocking

[Kateyru]

Touching base again. I started my 2nd shock attack on 5/8 after messing up the first time, i.e., I didn't keep FC > 15 ppm long enough to kill all the algae. About the time I started 2nd attack, I ran out of reagent so used dilution testing until new reagent arrived. Using dilution testing then FC testing with K-2006 kit when replacement reagent arrived, I've tried to keep FC at or above 15. So, this is day 12. I was out of town for a couple of days this past week and am aware that FC got below 15 a couple of times. How much of a setback is that? I didn't lose any FC from last night until this morning. My plan, per forum guidance, is to stay at or above 15 for an extra day, that is, 1 full day after no chlorine loss overnight. That would be today if the 2 recent dips below 15 don't have a significant effect overall. Guidance please.
Thanks!

[Watermom]

You are right to give it the extra day as long as there is still no more than a 1ppm chlorine loss overnight from sundown to sunup and you don't have a CC reading.

[Kateyru]

FC was at 17 at 7:30 am. I added 3 qts. of bleach at that time since I knew I would be gone for a few hours. At 1:30 pm, FC was 15. I added another 3 qts. of bleach. At 4:30 pm, FC was 16. I was gone again for a few hours. I didn't add more bleach since it was 4:30 in the afternoon. Got home and checked FC again at 8:30 pm, and it was 13.5. I lost 2.5 ppm between 4:30 and 8:30 in the late afternoon/evening. Seems like a lot. I've added another 3 qts of bleach now (at 8:30 pm). That seemed the way to go rather than worrying about chlorine loss. Is this loss excessive for time of day? Sun sets about 7:30 pm and it's hot (mid 80's) but sun is off the pool by 5:30 pm or so. So, is the loss due to sunlight? Does stubborn, refuse-to-die algae exist???? I feel like I have been shocking for ages.
Thanks.

[PoolDoc]

Bleach loss during the day is likely sunlight. You can really only tell what your non-solar loss is, by comparing late PM to early AM readings.

What is your CYA level?

[Kateyru]

The last time I checked CYA was 5/8 and it was 40. I've been following Janet's recommendation to focus on FC and not worry about anything else. This morning at 6:30, FC was 16.5 and CC = 0. I had not been checking CC but did today since Watermom said to. I added 3 more qts of bleach and turned SWG on as I was not sure I could get home until late afternoon. Trying to make sure FC stays over 15.

[PoolDoc]

Do you still have visible algae?
Where? What does it look like?

Also, it's probably time to retest your CYA level.

[Kateyru]

No visible algae. Water looks good, nice and clear. I'll retest CYA this afternoon. Do you think I can let FC drift down or do I need to keep it at or above 15 for another day? Am really hoping for a clean pool by this weekend!
Thanks so much!